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Conjugation-regulated self-assembled molecules for tandem solar cells

Published: 11/04/2026, 12:00 AM

Nature (2026) Cite this article Perovskite/silicon tandem solar cells on rough textured substrates are at present limited by a critical trade-off in self-assembled monolayer (SAM) design because increasing molecular conjugation enhances conductivity but often leads to unfavourable aggregation that impairs conformal coverage1,2. Here we overcome this challenge using a rationally engineered molecular spatial conjugation that incorporates tailored intramolecular distortion to suppress excess π–π stacking without sacrificing charge-transport efficiency. This steric regulation facilitates the formation of a highly ordered, conformal SAM across rough pyramidal textures. By reconciling molecular packing with interfacial coverage, the tailored interface provides optimized energy-level alignment for ultrafast charge extraction, enables improved defect passivation through adaptive conformational adjustment and acts as a robust template for high-quality perovskite film growth. Making use of this interface, the optimized tandem device achieves a notable fill factor (FF) of 85%, yielding a certified stabilized power conversion efficiency (PCE) of 35.1%. Furthermore, the device demonstrates outstanding stability, retaining more than 94% of its initial performance after 1,500 h of ageing under the ISOS-L-1 protocol. Our findings provide a clear molecular engineering route to reconcile conductivity and film uniformity while maximizing the performance of tandem photovoltaics on textured silicon substrates. This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription Prices may be subject to local taxes which are calculated during checkout All data are available in the main text or Supplementary Information. The data that support the findings of this study are available from the corresponding authors on request. Jia, L. et al. Efficient perovskite/silicon tandem with asymmetric self-assembly molecule. Nature 644, 912–919 https://doi.org/10.1038/s41586-025-09333-z (2025). Article ADS CAS PubMed Google Scholar Wu, W. et al. Stable and uniform self-assembled organic diradical molecules for perovskite photovoltaics. Science 389, 195–199 https://doi.org/10.1126/science.adv4551 (2025).